Autism Spectrum Disorders (ASD’s) are complex, controversial, and confounding conditions that have been extensively studied by a multi-disciplinary scientific community dedicated to unraveling the enigma of their etiologies. Investigations havemultiplied exponentially, in parallel with increasingASD prevalence rates. Yet, despite intensive research conducted by investigators whose specific areas of expertise involve one or another of the myriad variables presumed to be causally linked to ASD, the results, while enlightening, have provided few answers to core questions. In retrospect, obstacles to reaching clarity about these debilitating disorders of childhood onset have arisen, in part, due to traditional pursuit by the medical and psychological scientific communities of that one single common pathway or single mechanism that might lead to successful therapeutic intervention. A now voluminous literature has greatly enhanced our understanding about features of these incapacitating childhood conditions and has broadened understanding of underlying neural substrates, genetic contributions, and socioenvironmental moderators. A consequence of this recent work is the recognition that the often successful search in medicine for a unitary answer is unlikely to be applicable to this particular set of puzzling conditions. Regrettably, a prolific literature made possible by an expenditure of enormous professional and financial resources has not yet yielded a clearer picture of core aspects such as causal factors, differential developmental trajectories, treatment efficacy, or potential for recovery. Nonetheless, these foundational studies support a new era of investigation in which it is anticipated that there will be major progress regarding this major public health problem. As the papers in this Special Issue elaborate, the absence of definitive answers necessitates that novel theoretical propositions be formulated, and tested by a scientific community that works in unison to integrate complementary but often disparate data into new, meaningful and replicable hypotheses. A re-conceptualization of the origin of these spectrum disorders is needed and seems possible, building on the existent rich database. The papers in this issue will aid the reader seeking clarity about historical antecedents of autism and ASD research, and about a range of highly pertinent areas of ongoing exploration, including etiologic parameters, neural substrates, diverse phenotypic presentations, genetic markers, variable developmental courses, potential treatments and educational and psychosocial interventions, the possibility of recovery, and impaired or preserved behavioral and neurocognitive outcomes. The search is ongoing for both parsimony and synthesis. The authors for this issue were encouraged to challenge readers to reformulate their own insights and to question preconceived notions about ASD. They did not disappoint. The assembled papers are of interest and value to those engaged either in clinical practice or conducting research, since both pursuits require a full appreciation for the history and course of the ASD diagnosis, knowledge about the associated developmental trajectory, recognition of the many avenues of related investigation, and understanding of contemporary issues and advanced methods now employed to disentangle this morass. The six papers in this special issue review contributions of numerous investigators who have studied specific components of ASD’s, and each presents new theoretical and/or clinical insights, often suggesting reinterpretation of Neuropsychol Rev (2008) 18:271–272 DOI 10.1007/s11065-008-9070-1